diff --git a/ChatCommands.cc b/ChatCommands.cc
index b50cbd79..b418bdad 100644
--- a/ChatCommands.cc
+++ b/ChatCommands.cc
@@ -1,5 +1,7 @@
 #include "ChatCommands.hh"
 
+#include <string.h>
+
 #include <vector>
 #include <string>
 #include <unordered_map>
diff --git a/Compression.cc b/Compression.cc
index 92f56f8f..31b593c4 100644
--- a/Compression.cc
+++ b/Compression.cc
@@ -102,7 +102,7 @@ string prs_compress(const string& data) {
   prs_compress_ctx pc;
 
   ssize_t read_offset = 0;
-  while (read_offset < data.size()) {
+  while (read_offset < static_cast<ssize_t>(data.size())) {
 
     // look for a chunk of data in history matching what's at the current offset
     ssize_t best_offset = 0;
@@ -263,7 +263,7 @@ size_t prs_decompress_size(const string& data, size_t max_size) {
   size_t output_size = 0;
   StringReader r(data.data(), data.size());
 
-  int32_t r3, r5;
+  int32_t r3;
   int bitpos = 9;
   int16_t currentbyte; // int16_t because it can be -1 when EOF occurs
   int flag;
@@ -321,7 +321,6 @@ size_t prs_decompress_size(const string& data, size_t max_size) {
         return output_size;
       }
       r3 = r3 & 0x00000007;
-      r5 = (offset >> 3) | 0xFFFFE000;
       if (r3 == 0) {
         flag = 0;
         r3 = get_u8_or_eof(r);
@@ -353,7 +352,6 @@ size_t prs_decompress_size(const string& data, size_t max_size) {
         return output_size;
       }
       r3 += 2;
-      r5 = offset | 0xFFFFFF00;
     }
     if (r3 == 0) {
       continue;
diff --git a/DNSServer.cc b/DNSServer.cc
index a1a83a95..a7e5e5f9 100644
--- a/DNSServer.cc
+++ b/DNSServer.cc
@@ -1,6 +1,7 @@
 #include "DNSServer.hh"
 
 #include <stdio.h>
+#include <string.h>
 #include <unistd.h>
 #include <poll.h>
 #include <netinet/in.h>
diff --git a/Items.cc b/Items.cc
index 7e92df6e..4224e1a6 100644
--- a/Items.cc
+++ b/Items.cc
@@ -1,5 +1,7 @@
 #include "Items.hh"
 
+#include <string.h>
+
 #include <phosg/Random.hh>
 
 using namespace std;
@@ -143,22 +145,23 @@ void player_use_item_locked(shared_ptr<Lobby> l, shared_ptr<Client> c,
     size_t item_index) {
 
   ssize_t equipped_weapon = -1;
-  ssize_t equipped_armor = -1;
-  ssize_t equipped_shield = -1;
-  ssize_t equipped_mag = -1;
+  // ssize_t equipped_armor = -1;
+  // ssize_t equipped_shield = -1;
+  // ssize_t equipped_mag = -1;
   for (size_t y = 0; y < c->player.inventory.num_items; y++) {
     if (c->player.inventory.items[y].equip_flags & 0x0008) {
       if (c->player.inventory.items[y].data.item_data1[0] == 0) {
         equipped_weapon = y;
-      } else if ((c->player.inventory.items[y].data.item_data1[0] == 1) &&
-                 (c->player.inventory.items[y].data.item_data1[1] == 1)) {
-        equipped_armor = y;
-      } else if ((c->player.inventory.items[y].data.item_data1[0] == 1) &&
-                 (c->player.inventory.items[y].data.item_data1[1] == 2)) {
-        equipped_shield = y;
-      } else if (c->player.inventory.items[y].data.item_data1[0] == 2) {
-        equipped_mag = y;
       }
+      // else if ((c->player.inventory.items[y].data.item_data1[0] == 1) &&
+      //            (c->player.inventory.items[y].data.item_data1[1] == 1)) {
+      //   equipped_armor = y;
+      // } else if ((c->player.inventory.items[y].data.item_data1[0] == 1) &&
+      //            (c->player.inventory.items[y].data.item_data1[1] == 2)) {
+      //   equipped_shield = y;
+      // } else if (c->player.inventory.items[y].data.item_data1[0] == 2) {
+      //   equipped_mag = y;
+      // }
     }
   }
 
diff --git a/LevelTable.cc b/LevelTable.cc
index 65acbea7..dc0f83c5 100644
--- a/LevelTable.cc
+++ b/LevelTable.cc
@@ -1,5 +1,7 @@
 #include "LevelTable.hh"
 
+#include <string.h>
+
 #include <phosg/Filesystem.hh>
 
 #include "Compression.hh"
diff --git a/License.cc b/License.cc
index b08d0283..967ca12b 100644
--- a/License.cc
+++ b/License.cc
@@ -43,8 +43,9 @@ LicenseManager::LicenseManager(const std::string& filename) : filename(filename)
     auto licenses = load_vector_file<License>(this->filename);
     for (const auto& read_license : licenses) {
       shared_ptr<License> license(new License(read_license));
+      uint32_t serial_number = license->serial_number;
       this->bb_username_to_license.emplace(license->username, license);
-      this->serial_number_to_license.emplace(license->serial_number, license);
+      this->serial_number_to_license.emplace(serial_number, license);
     }
 
   } catch (const cannot_open_file&) {
@@ -124,7 +125,8 @@ void LicenseManager::ban_until(uint32_t serial_number, uint64_t end_time) {
 void LicenseManager::add(shared_ptr<License> l) {
   {
     rw_guard g(this->lock, true);
-    this->serial_number_to_license.emplace(l->serial_number, l);
+    uint32_t serial_number = l->serial_number;
+    this->serial_number_to_license.emplace(serial_number, l);
     if (l->username[0]) {
       this->bb_username_to_license.emplace(l->username, l);
     }
diff --git a/Lobby.cc b/Lobby.cc
index 42fc1d43..10852c5b 100644
--- a/Lobby.cc
+++ b/Lobby.cc
@@ -1,5 +1,7 @@
 #include "Lobby.hh"
 
+#include <string.h>
+
 #include "SendCommands.hh"
 #include "Text.hh"
 
diff --git a/PSOEncryption.cc b/PSOEncryption.cc
index 2a5673ac..a666ab10 100644
--- a/PSOEncryption.cc
+++ b/PSOEncryption.cc
@@ -299,11 +299,9 @@ void PSOBBEncryption::decrypt(void* vdata, size_t size) {
   size >>= 3;
 
   uint32_t* data = reinterpret_cast<uint32_t*>(vdata);
-  uint32_t eax, ecx, edx, ebx, ebp, esi, edi;
+  uint32_t edx, ebx, ebp, esi, edi;
 
   edx = 0;
-  ecx = 0;
-  eax = 0;
   while (edx < size) {
     ebx = data[edx];
     ebx = ebx ^ this->stream[5];
@@ -337,11 +335,9 @@ void PSOBBEncryption::encrypt(void* vdata, size_t size) {
   size >>= 3;
 
   uint8_t* data = reinterpret_cast<uint8_t*>(vdata);
-  uint32_t eax, ecx, edx, ebx, ebp, esi, edi;
+  uint32_t edx, ebx, ebp, esi, edi;
 
   edx = 0;
-  ecx = 0;
-  eax = 0;
   while (edx < size) {
     ebx = data[edx];
     ebx = ebx ^ this->stream[0];
diff --git a/PSOProtocol.cc b/PSOProtocol.cc
index 22b8a65d..a74aa906 100644
--- a/PSOProtocol.cc
+++ b/PSOProtocol.cc
@@ -1,5 +1,9 @@
 #include "PSOProtocol.hh"
 
+#include <stdexcept>
+
+using namespace std;
+
 
 
 uint16_t PSOCommandHeader::command(GameVersion version) const {
@@ -13,6 +17,7 @@ uint16_t PSOCommandHeader::command(GameVersion version) const {
     case GameVersion::BB:
       return reinterpret_cast<const PSOCommandHeaderBB*>(this)->command;
   }
+  throw logic_error("unknown game version");
 }
 
 uint16_t PSOCommandHeader::size(GameVersion version) const {
@@ -26,6 +31,7 @@ uint16_t PSOCommandHeader::size(GameVersion version) const {
     case GameVersion::BB:
       return reinterpret_cast<const PSOCommandHeaderBB*>(this)->size;
   }
+  throw logic_error("unknown game version");
 }
 
 uint32_t PSOCommandHeader::flag(GameVersion version) const {
@@ -39,5 +45,6 @@ uint32_t PSOCommandHeader::flag(GameVersion version) const {
     case GameVersion::BB:
       return reinterpret_cast<const PSOCommandHeaderBB*>(this)->flag;
   }
+  throw logic_error("unknown game version");
 }
 
diff --git a/Quest.cc b/Quest.cc
index 3d8fd67b..5ccd9d33 100644
--- a/Quest.cc
+++ b/Quest.cc
@@ -1,5 +1,6 @@
 #include "Quest.hh"
 
+#include <algorithm>
 #include <string>
 #include <unordered_map>
 #include <phosg/Filesystem.hh>
@@ -330,7 +331,8 @@ QuestIndex::QuestIndex(const char* directory) : directory(directory) {
     string full_path = this->directory + "/" + filename;
 
     if (ends_with(filename, ".gba")) {
-      this->gba_file_contents.emplace(filename, new string(load_file(full_path)));
+      shared_ptr<string> contents(new string(load_file(full_path)));
+      this->gba_file_contents.emplace(make_pair(filename, contents));
       continue;
     }
 
diff --git a/Quest.hh b/Quest.hh
index 909a453d..ef28b37a 100644
--- a/Quest.hh
+++ b/Quest.hh
@@ -3,7 +3,9 @@
 #include <stdint.h>
 
 #include <map>
+#include <memory>
 #include <string>
+#include <vector>
 
 #include "Version.hh"
 
diff --git a/README.md b/README.md
index 7880123b..08766088 100644
--- a/README.md
+++ b/README.md
@@ -24,7 +24,10 @@ This project is primarily for my own nostalgia. Feel free to peruse if you'd lik
 
 ## Usage
 
+Currently this code should build on macOS and Ubuntu. It might build on other Linux flavors, but don't expect it to work on Windows at all.
+
 So, you've read all of the above and you want to try it out? Here's what you do:
+- Make sure you have libreadline installed (use Homebrew in macOS, or install libreadline-dev in Linux).
 - Build and install phosg (https://github.com/fuzziqersoftware/phosg).
 - Run `make`.
 - Edit system/config.json to your liking.
diff --git a/ReceiveCommands.cc b/ReceiveCommands.cc
index 62639c8c..9f118474 100644
--- a/ReceiveCommands.cc
+++ b/ReceiveCommands.cc
@@ -1,6 +1,7 @@
 #include "SendCommands.hh"
 
 #include <inttypes.h>
+#include <string.h>
 
 #include <memory>
 #include <phosg/Filesystem.hh>
diff --git a/ReceiveSubcommands.cc b/ReceiveSubcommands.cc
index b7bbca3f..88cec0d7 100644
--- a/ReceiveSubcommands.cc
+++ b/ReceiveSubcommands.cc
@@ -1,5 +1,7 @@
 #include "ReceiveSubcommands.hh"
 
+#include <string.h>
+
 #include <memory>
 #include <phosg/Strings.hh>
 
diff --git a/SendCommands.cc b/SendCommands.cc
index 56c1e42a..11d65107 100644
--- a/SendCommands.cc
+++ b/SendCommands.cc
@@ -1,5 +1,7 @@
 #include "SendCommands.hh"
 
+#include <string.h>
+
 #include <memory>
 #include <phosg/Encoding.hh>
 #include <phosg/Random.hh>
diff --git a/Server.cc b/Server.cc
index 5808fa5c..2b05e4aa 100644
--- a/Server.cc
+++ b/Server.cc
@@ -128,7 +128,8 @@ void Server::on_listen_accept(Server::WorkerThread& wt,
 
   struct bufferevent *bev = bufferevent_socket_new(wt.base.get(), fd,
       BEV_OPT_CLOSE_ON_FREE | BEV_OPT_THREADSAFE | BEV_OPT_DEFER_CALLBACKS | BEV_OPT_UNLOCK_CALLBACKS);
-  auto emplace_ret = wt.bev_to_client.emplace(bev, new Client(bev, version, initial_state));
+  shared_ptr<Client> c(new Client(bev, version, initial_state));
+  auto emplace_ret = wt.bev_to_client.emplace(make_pair(bev, c));
   this->client_count++;
 
   bufferevent_setcb(bev, &WorkerThread::dispatch_on_client_input, NULL,
@@ -231,7 +232,7 @@ void Server::receive_and_process_commands(shared_ptr<Client> c, struct buffereve
   new_bytes &= ~(header_size - 1); // only read in multiples of header_size
   c->recv_buffer.resize(existing_bytes + new_bytes);
   void* recv_ptr = const_cast<char*>(c->recv_buffer.data() + existing_bytes);
-  if (evbuffer_remove(buf, recv_ptr, new_bytes) != new_bytes) {
+  if (evbuffer_remove(buf, recv_ptr, new_bytes) != static_cast<ssize_t>(new_bytes)) {
     throw runtime_error("some bytes could not be read from the receive buffer");
   }